glibc/io/lockf.c
Adhemerval Zanella e442e40de5 io: Consolidate lockf implementation
With internal fcntl64 internal (commit 06ab719d), it is possible to
consolidate lockf implementation by using the LFS fcntl interface
instead of using arch and system-specific implementations.

For Linux, the i386 implementation is used as generic implementation
by replacing the direct syscall with fcntl64 call.  The LFS symbol
alias for default LFS ABI (__OFF_T_MATCHES_OFF64_T) is used to avoid
the duplicate symbol (instead of overriding the implementation with an
empty file).

For Hurd lockf64 semantic is changed: previous generic lockf64
implementation returned EOVERFLOW if LEN input is larger than 32-bit
off_t.  However, Hurd fcntl64 implementation for F_GETLK64, F_SETLK64,
and F_SETLKW64 do accept off64_t inputs (__f_setlk accepts only off64_t
inputs).

Checked on i686-linux-gnu and x86_64-linux-gnu along with a i686-gnu
build.

	* io/Makefile (tests): Add tst-lockf.
	* io/lockf.c (lockf): Use __fcntl and only define for
	!__OFF_T_MATCHES_OFF64_T.
	* io/lockf64.c (__lockf64): Call __fcntl64 and alias to lockf for
	__OFF_T_MATCHES_OFF64_T case.
	* io/tst-lockf.c: New file.
	* sysdeps/unix/sysv/linux/i386/lockf64.c: Remove file.
	* sysdeps/unix/sysv/linux/arm/lockf64.c: Likewise.
	* sysdeps/unix/sysv/linux/m68k/lockf64.c: Likewise.
	* sysdeps/unix/sysv/linux/mips/mips32/lockf64.c: Likewise.
	* sysdeps/unix/sysv/linux/mips/mips64/n32/lockf64.c: Likewise.
	* sysdeps/unix/sysv/linux/powerpc/powerpc32/lockf64.c: Likewise.
	* sysdeps/unix/sysv/linux/s390/s390-32/lockf64.c: Likewise.
	* sysdeps/unix/sysv/linux/sh/lockf64.c: Likewise.
	* sysdeps/unix/sysv/linux/sparc/sparc32/lockf64.c: Likewise.
2019-02-15 18:45:39 -02:00

62 lines
1.9 KiB
C

/* Copyright (C) 1994-2019 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<http://www.gnu.org/licenses/>. */
#ifndef __OFF_T_MATCHES_OFF64_T
#include <unistd.h>
#include <fcntl.h>
#include <errno.h>
/* lockf is a simplified interface to fcntl's locking facilities. */
int
lockf (int fd, int cmd, off_t len)
{
/* lockf is always relative to the current file position. */
struct flock fl = {
.l_type = F_WRLCK,
.l_whence = SEEK_CUR,
.l_len = len
};
/* lockf() is a cancellation point but so is fcntl() if F_SETLKW is
used. Therefore we don't have to care about cancellation here,
the fcntl() function will take care of it. */
switch (cmd)
{
case F_TEST:
/* Test the lock: return 0 if FD is unlocked or locked by this process;
return -1, set errno to EACCES, if another process holds the lock. */
fl.l_type = F_RDLCK;
if (__fcntl (fd, F_GETLK, &fl) < 0)
return -1;
if (fl.l_type == F_UNLCK || fl.l_pid == __getpid ())
return 0;
__set_errno (EACCES);
return -1;
case F_ULOCK:
fl.l_type = F_UNLCK;
return __fcntl (fd, F_SETLK, &fl);
case F_LOCK:
return __fcntl (fd, F_SETLKW, &fl);
case F_TLOCK:
return __fcntl (fd, F_SETLK, &fl);
}
__set_errno (EINVAL);
return -1;
}
#endif